Mid 30s. I have a small but slowly growing stock portfolio. If I keep going the way I am, in 5 years I might be able to buy a Model 3 with its worth. My family growing up invested in my education, not in a stock portfolio, so what I have is skills, not cash.

Then maybe add more because the market returns are suppose say 5%, but they are generally much more higher, around 10% over a 15-year period. Over 14-years that money doubles, but the market is performing at 10%, and even higher lately, so that's 7 years. So instead of buying that model 3 in 5-years if you continue adding small increments that Model 3 turns into a Model S in 7-years.

The issue is many people hold a savings account in cash but then inflation eats you up, or they store it in a savings account, but then you break even with inflation. Taking advantage of compound interest is huge.

And a Roth IRA for the kid as soon as they start working. Have them contribute 100% of their pay and then give them the same amount to use. I plan to do this with my kid.